The present invention relates generally to carpets, and more particularly to automotive tufted carpet having a double primary backing for providing necessary physical properties including moldability while also providing enhanced acoustical performance.
In the past, tufted carpeting for automobiles was made by tufting yarn into a backing of woven jute or the like. The jute backing was heavy and relatively stable, so one coated the back with latex or other adhesives only to lock in the tufts and the carpet was ready to installed. More recently, however, lightweight materials such as woven polypropylene tape and polyester spunbonds have been used as the primary backing through which yarn is tufted and a secondary backing of a stable material is adhered to the back of the carpet by an adhesive. Presently, popular primary backings are polypropylene and polyester formed from either woven or non-woven or spunbond materials. Such backings are preferred due to their light weight and performance. Typically, after face yarns are tufted into the primary backing, the resulting carpet is back coated with an adhesive to lock in the stitches.
Another example of a conventional tufted carpet for automotive end use would provide a layer of LUTRADUR(copyright) spunbonded polyester (available from Freudenberg Nonwovens NA) that is tufted with face yams that are typically nylon (polyamide) or the like. Next, a polyethylene pre-coat followed by a polyethylene coating is applied in a manner well known to those skilled in the art to manufacture an automotive tufted carpet. This type of carpet construction, however, does not provide much in the way of noise dampening or acoustical properties that would serve to minimize external and internal noise in an automobile. Previously, efforts have been made to provide a noise dampening automotive tufted carpet by tufting face yarns into a primary backing of LUTRADUR(copyright) spunbonded polyester and then pre-coating the tufted carpet with a suitable pre-coat such as polyethylene. Next, a layer of EVA Mass Back with a preferred weight of about 30 to 80 ounces/yard2 is adhered to the tufted carpet in order to provide a noise dampening layer to the automotive tufted carpet. The resulting automotive tufted carpet is acoustically superior to previously known automotive tufted carpet but is relatively heavy and still leaves much to be desired in acoustical performance characteristics.
Although not intended to address acoustical shortcomings of automotive tufted carpet, the prior art does include some rugs or carpets having a plurality of primary backings. For example, U.S. Pat. No. 2,713,012 to Hartstein discloses a tufted rug having dual primary backings of cotton and jute or the like. The Hartstein patent does not contemplate back coating of the rug, and relies on the double backing to assist in holding in the tufts. Also, the jute backing is heavy enough to stabilize the carpet. U.S. Pat. No. 4,426,415 to Avery discloses a carpet in the nature of artificial turf having a plurality of primary backings, the backings varying in fineness from bottom to top of the carpet. All of the plurality of backings are the same material, and polypropylene is specifically mentioned. Since Avery contemplates back coating of the carpet, the problem of stretching and distorting will be present, though perhaps somewhat slightly reduced due to the greater strength of multiple backings. U.S. Pat. No. 4,705,706 to Avery discloses a multiple primary backing, but the backing may be NYLON(copyright) or the like while the face yarn is polypropylene so the back stitch can be set by heat rather than by a separately applied adhesive.
Finally, U.S. Pat. No. 5,962,101 to Irwin, Sr. et al provides a tufted carpet having a double primary backing wherein one layer of the backing is a conventional backing of polypropylene or the like and the other layer is an open weave material having greater strength and less stretch than conventional backing. The face yarns are tufted through both parts of the double backing which secures the two backings together. An adhesive coating is applied over the back of the tufted carpet, and the double primary backing provides a dimensionally stable carpet during the adhesive coating process and without the application of a secondary backing. However, the carpet may by choice have conventional woven or non-woven sheet materials adhered thereto as a secondary backing. Irwin, Sr. et al. specifically discloses that the upper layer of the two-layer backing will be a conventional woven or non-woven backing material such as polypropylene. The lower layer of the two-layer primary backing is an open weave material that may comprise a leno weave having mono-filaments or tape yarn in the warp direction and a spun/fiber in the filling direction. For maximum stability, the lower layer will be formed of fiberglass or the like. None of the two layer primary backing prior art known to applicant addresses the objective of the present invention to provide an automotive tufted carpet having enhanced acoustical properties.
Also prior art of interest, applicant notes German Patent No. 100 09 281 to Emirze et al. (and assigned to the parent company of the assignee of the present invention) which discloses a new sound-absorbent material and process for making the material which comprises a micro-filament non-woven with a weight of about 40 to 300 grams/meter2. Preferably, the sound-absorbent material is one in which the non-woven consists of melt-spun, aerodynamically stretched multi-component endless filaments woven directly into a fleece with a titer of 1.5 to 3 dtex, and wherein the multi-component endless filaments are split and bonded to an extent of at least 80% into micro-endless filaments with a titer of 0.1 to 0.3 dtex. The sound-absorbent material is one in which the multi-component endless filaments comprise (1) a cross section with an orange-like multi-segment structure (pie) where the segments alternately contain one of the two incompatible polymers or comprise (2) a side-by-side (ss) configuration of the incompatible polymers in the multi-component endless filaments. The process of the invention provides for manufacturing the sound-absorbent material comprising multi-component endless filaments being spun from the melt, stretched and then woven directly into a fleece, followed by pre-bonding, after which the non-woven is fully bonded by high-pressure fluid jets and simultaneously split into micro-endless filaments with a titer of 0.1 to 1.2 dtex. Emirze et al. discloses that the sound-absorbent material is suitable for many end uses including tuft backing for automotive tufted carpet since it possesses at least equally good sound-absorbent properties as conventional automobile carpets while using significantly less material since heavy carpet backings can be dispensed with. Other uses of the sound-absorbent material include headliner construction, pillar, floor and trunk trims, dashboard construction, engine compartment and/or floor trim, and the like. The sound-absorbent material disclosed in the patent is manufactured and sold by Freudenberg KG under the trade name EVOLON(copyright).
Emirze et al. does not disclose use of the sound-absorbent material as one layer of a double-layer or two-part primary backing for an automotive tufted carpet such as provided for by the present invention in order to provide a combination of the required physical properties for conventional automotive tufted carpets and the enhanced acoustical properties of the novel automotive tufted carpet of the invention. Emirze et al. merely discloses use of the sound-absorbent material for a number of uses including as the primary backing for automotive tufted carpet.
It will therefore be seen that the prior art in both automotive tufted carpets and sound absorbent materials has not provided a solution to the problem of providing an automotive tufted carpet that possesses the required moldability of conventional automotive tufted carpet while also providing enhanced acoustical properties that are greatly desirable in the manufacture of modern automobiles. Thus, applicant has discovered a novel construction for an automotive tufted carpet that provides unexpected and surprising enhancements in acoustical properties that are much to be desired in the manufacture of modern automotive tufted carpets.
The present invention provides an automotive tufted carpet having improved acoustic properties and comprising a two-layer primary backing including a first backing formed of a woven or non-woven or spunbond material; a second backing formed of a micro-filament spunlaced materials; and an adhesive web between the first backing and the second backing serving to facilitate thermobonding the first backing and second backing together. A plurality of tufts of yarn are sewn through the two-layer primary backing.
The present invention also includes a method for making the automotive tufted carpet comprising bringing together a first backing formed of a woven or non-woven or spunbond material; a second backing formed of a micro-filament spunlaced material; and an adhesive web positioned between the first backing and the second backing. Heat is applied during processing to the adhesive web such that the adhesive web acts to thermobond the first backing and second backing together to form a primary backing composite. Finally, the first backing and second backing are fed through a tufting machine and tufts of yarn sewn through both of the first backing and second backing to provide face yarns on one of the first and second backings.
The automotive tufted carpet possesses the requisite strength and moldability of conventional automotive tufted carpet while also being provided with surprising and unexpectedly superior acoustical properties so as to assist in minimizing the noise level in an automobile.